ε-Zn（OH）2 crystals with high thermal stability,well crystallinity and fine dispersity were prepared by aging at low temperatue from zinc nitrate and sodium hydroxide in aqueous solution. The crystal structure,morph...ε-Zn（OH）2 crystals with high thermal stability,well crystallinity and fine dispersity were prepared by aging at low temperatue from zinc nitrate and sodium hydroxide in aqueous solution. The crystal structure,morphology and thermal stability were characterized by Xray diffractometry,scanning electron microscopy and differential scanning calorimeter. The influences of reaction temperatures,mole ratios of zinc nitrate to sodium hydroxide and phase-inversion rates on the products were discussed in details.展开更多
ZnO nanoparticles were synthesized via precipitation-pyrolysis (P&P), where the precursor zinc hydroxide carbonate (Zn5(CO3)2(OH)6) was obtained and then pyrolyzed. The results of TEM indicate that pyrolysis tempe...ZnO nanoparticles were synthesized via precipitation-pyrolysis (P&P), where the precursor zinc hydroxide carbonate (Zn5(CO3)2(OH)6) was obtained and then pyrolyzed. The results of TEM indicate that pyrolysis temperature is the predominant factor for controlling mean sizes of nanoparticles, ranging from 8 nm to 80 nm. Increasing the pyrolysis temperature enhances the mean size. The results of XRD show that nanoparticles are all of crystalline zincite. The mean size observed by TEM is in agreement with that calculated from the specific surface area(SSA) and the crystalline size calculated from the XRD patterns, indicating that the primary particles are rather uniform in size and have single crystals. The growth behaviors of epitaxy along the C-axis are responsible for the morphology of ZnO changing from sphere to rod-like shape, and then to reticulation. Compared with other synthesis approaches, P&P can get fairly good product with a relatively low cost.展开更多
文摘ε-Zn（OH）2 crystals with high thermal stability,well crystallinity and fine dispersity were prepared by aging at low temperatue from zinc nitrate and sodium hydroxide in aqueous solution. The crystal structure,morphology and thermal stability were characterized by Xray diffractometry,scanning electron microscopy and differential scanning calorimeter. The influences of reaction temperatures,mole ratios of zinc nitrate to sodium hydroxide and phase-inversion rates on the products were discussed in details.
基金Project(50371024) supported by the National Natural Science Foundation of China
文摘ZnO nanoparticles were synthesized via precipitation-pyrolysis (P&P), where the precursor zinc hydroxide carbonate (Zn5(CO3)2(OH)6) was obtained and then pyrolyzed. The results of TEM indicate that pyrolysis temperature is the predominant factor for controlling mean sizes of nanoparticles, ranging from 8 nm to 80 nm. Increasing the pyrolysis temperature enhances the mean size. The results of XRD show that nanoparticles are all of crystalline zincite. The mean size observed by TEM is in agreement with that calculated from the specific surface area(SSA) and the crystalline size calculated from the XRD patterns, indicating that the primary particles are rather uniform in size and have single crystals. The growth behaviors of epitaxy along the C-axis are responsible for the morphology of ZnO changing from sphere to rod-like shape, and then to reticulation. Compared with other synthesis approaches, P&P can get fairly good product with a relatively low cost.
